Re: Optimize kernel readahead using buffer access strategy

On Tue, Dec 10, 2013 at 5:03 AM, KONDO Mitsumasa
<kondo(dot)mitsumasa(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> I revise this patch and re-run performance test, it can work collectry in
> Linux and no complile wanings. I add GUC about enable_kernel_readahead
> option in new version. When this GUC is on(default), it works in
> POSIX_FADV_NORMAL which is general readahead in OS. And when it is off, it
> works in POSXI_FADV_RANDOM or POSIX_FADV_SEQUENTIAL which is judged by
> buffer hint in Postgres, readahead parameter is optimized by postgres. We
> can change this parameter in their transactions everywhere and everytime.

I'd change the naming to

enable_readahead=os|fadvise

with os = on, fadvise = off

And, if you want to keep the on/off values, I'd reverse them. Because
off reads more like "I don't do anything special", and in your patch
it's quite the opposite.